Download The Microprocessor

The Microprocessor
• An integrated circuit with millions of
transistors interconnected with very small
aluminum wires.
• Controls and directs activities of the PC
• Packaged in a form called PGA(Pin Grid
Array)
• Installs on a socket called ZIF(Zero
insertion force
CPU Packages
• DIPP- Dual Inline Package- Now obsolete
Formerly in 8088, 8086, and 80286. Had 2
rows of pins on either side
• PGA Pin Grid Array 80286,80386,486- pins
regularly distributed on bottom of CPU
• SPGA Staggared Pin Grid Array Pentiums,
uses diagonal pattern of pins. Package
smaller.
The 8086 Family:The Late 1970’s
• Could address up to 1 mb of memory at a
time when other CPU’s could only address
64 kb. The 16 bit external bus too powerful.
• The 8088 replaced the 8086 and had only an
8 bit external bus
• The 8088 CPU was the first chip used in
IBM’s microcomputers
The 80286 Family:1983
• Wanted to make the 286 backward
compatible with the 8088’s.
• So had 2 modes:
– Real mode-less powerful
– Protected mode-very powerful
• Could access up to 16 mb of memory
• Needed a special operating system
• But most users only had DOS
The 386 DX: 1985
• First true 32 bit chip, all buses 32 bits wide
• Capable of running in real mode, 286 protected
mode and its own 386 protected mode
• In 386 protected mode it had 2 new functions:
– Virtual memory- could use hard drive to pretend
that computer had up to 4 GB of data!
– Virtual 8086- 8086 bubbles created for DOS
The 386 SX:1988
• How different from the 386DX?
– External data bus reduced to 16 bits
– Address bus reduced to 24 bits, which limited
memory use to 16 mb
– First popular lap tops were based on the 386SX
but was called the 386 SL and ran on 3.3 volts
The 486DX:1989
• How different from the 386 family?
– A built in math coprocessor
• Performs high math functions
– A built in 8K cache on same chip
• This was an SRAM cache that stores code read in
the past. When the CPU asks for the code again, it
doesn’t have to go to DRAM to get it.
486SX:1991
• Same as 486 DX except the math coprocessor is disabled.
The Pentiums:1993
• Had 64 bit external data bus that split
internally as 2 dual pipelined 32 bit buses
• Supported an 8K write through cache for
programs
• Most early pentiums ran at 3.3 volts. This
conserved heat. Voltage regulators on the
motherboard can decrease voltage
Pentiums continued
• Includes clock doubling through the setting
of jumpers
• Most later Pentuims use SPGA, Standard
Pin Grid Array. This allows staggers the
pens and allows for higher pen density
Pentium Pro(P6):1995
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Quad pipelining
Dynamic processing
On chip L2 cache
Uses Socket 8, only CPU that does
Too powerful for most users, never really
caught on
Recent Pentiums:After 1996
• MMX- helps with multimedia products
• Increased multipliers/clocks- 45 multipliers
• Improved processing- better cache branch
predicting
• Split voltage- 2 voltages, not backward compatible
• AMD AND CYRIX HAVE MADE GREAT
STRIDES IN CPU BUSINESS WITH THE
NEW ABOVE TECHNOLOGIES
Pentium II: 1997
• Had new SEC cartridge to be inserted into
on motherboard. This replaced the old ZIF
SPGA socket 7 connection.